BIOLOGICAL CONSTRAINTS ON TUNING IN THE INNER EAR

Peter Narins, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01DC000222-16 from National Institute On Deafness And Other Communication Disorders, IRG: HAR

Abstract: The overall goal of the proposed research is a richer understanding of the structural and physiological bases of frequency selectivity in the vertebrate auditory system. In particular, the primary objectives of the proposed research are to gain an understanding and appreciation of the mechanical and electrical factors underlying frequency resolution in the vertebrate auditory system, and to provide further insights into the mechanisms underlying stimulus interactions which affect tuning in the vertebrate inner ear. To accomplish the first objective, we intend to perform a series of three detailed investigations in order to (a) directly measure the motion of the tectorial membrane partition in response to sound and thus more precisely define the role of this structure in frequency analysis, (b) characterize in situ the temperature dependence of the tectorial membrane partition in its response to pure tones, and (c) systematically study the membrane properties of anatomically-defined hair cells from the amphibian papilla, and to relate these properties to the known tonotopic organization of the organ. To accomplish the second objective, we shall (d) extend our investigation of the interactions between acoustic and seismic stimuli on the recently characterized bimodal fibers in the eighth nerve, and (e) quantify the extent to which the extratympanic pathways to the inner ear play a role in sculpting the tuned responses of the peripheral auditory system. We believe that the data that result from this combined structure-function and neurethological approach will be rich in implications regarding the anatomical and neural substrate underlying the processing of complex sounds, and that this work will serve as a model for understanding fundamental problems of human speech perception in noisy environments.

Keywords: biomechanics, hearing, labyrinth, sound frequency, acoustic nerve (VIII), auditory stimulus, ear hair cell, temperature, vibration perception, Anura, heterodyning, patch clamp

Project start date: 1983-07-01

Project end date: 2000-06-30

5R01DC000222-16 (1999): $292784

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BIOLOGICAL CONSTRAINTS ON TUNING IN THE INNER EAR

Peter Narins, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01DC000222-15 from National Institute On Deafness And Other Communication Disorders, IRG: HAR

Abstract: The overall goal of the proposed research is a richer understanding of the structural and physiological bases of frequency selectivity in the vertebrate auditory system. In particular, the primary objectives of the proposed research are to gain an understanding and appreciation of the mechanical and electrical factors underlying frequency resolution in the vertebrate auditory system, and to provide further insights into the mechanisms underlying stimulus interactions which affect tuning in the vertebrate inner ear. To accomplish the first objective, we intend to perform a series of three detailed investigations in order to (a) directly measure the motion of the tectorial membrane partition in response to sound and thus more precisely define the role of this structure in frequency analysis, (b) characterize in situ the temperature dependence of the tectorial membrane partition in its response to pure tones, and (c) systematically study the membrane properties of anatomically-defined hair cells from the amphibian papilla, and to relate these properties to the known tonotopic organization of the organ. To accomplish the second objective, we shall (d) extend our investigation of the interactions between acoustic and seismic stimuli on the recently characterized bimodal fibers in the eighth nerve, and (e) quantify the extent to which the extratympanic pathways to the inner ear play a role in sculpting the tuned responses of the peripheral auditory system. We believe that the data that result from this combined structure-function and neurethological approach will be rich in implications regarding the anatomical and neural substrate underlying the processing of complex sounds, and that this work will serve as a model for understanding fundamental problems of human speech perception in noisy environments.

Keywords: biomechanics, hearing, labyrinth, sound frequency, acoustic nerve (VIII), auditory stimulus, ear hair cell, temperature, vibration perception, Anura, heterodyning, patch clamp

Project start date: 1983-07-01

Project end date: 2000-06-30

5R01DC000222-15 (1998): $282147

5R01DC000222-14 (1997): $214270

AUDITORY SYSTEM RESPONSE TO AIRBORNE AND SEISMIC STIMULI

Peter Narins, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01DC000222-22 from National Institute On Deafness And Other Communication Disorders, IRG: ZRG1

Abstract: The overall goal of the proposed research is a quantitative of the structural and physiological constraints on low-frequency selectivity in the vertebrate auditory system. In particular, the primary objectives of the proposed research are to gain an understanding and appreciation of the mechanical and electrical factors underlying airborne, substrate-borne and combination (bimodal) stimulus reception, and to provide further insight into the mechanisms underlying stimulus interactions which affect tuning in the vertebrate inner ear. To accomplish these objectives, a series of five detailed investigations will be performed in order to a (a) directly measure the motion of the middle ear ossicles in amphibians in response to airborne sound, substrate-borne vibration and bimodal stimulation, and thus more precisely define the role of these structures in low-frequency reception, (b) characterize the airborne and seismic response properties of the middle ear ossicles of two other "low- frequency" animals- the common and golden mole- and thus extend our observations to fossorial mammals, (c) quantify the extent to which the tectorial membrane responds to low-frequency sound and vibration in order to elucidate the role of this structure in bimodal processing, (d) systematically compare synaptic release in low-frequency (bimodal) and high-frequency (unimodal) hair cells from the amphibian papilla by tracking correlated capacitance changes in response to depolarization, and (e) extend our investigation of the nonlinear interactions between acoustic and seismic stimuli to the bimodal fibers in the eighth nerve. The data that result from this integrative structure-functional and neuroethological approach will be rich in implications regarding the anatomical and neural substrates underlying the processing of sound-vibration complexes; thus this work is expected to provide a framework for understanding the relationship between air-conducted and bone-conducted sound transmission in animals, including humans.

Keywords: auditory ossicle, auditory pathway, auditory stimulus, ear hair cell, neural information processing, sound frequency, vibration, Amphibia, Mammalia, Rana, voltage /patch clamp

Project start date: 1983-07-01

Project end date: 2006-06-30

5R01DC000222-22 (2005): $150000

5R01DC000222-21 (2004): $448038

5R01DC000222-20 (2003): $435032

5R01DC000222-19 (2002): $272066

5R01DC000222-18 (2001): $413134

BIOLOGICAL CONSTRAINTS ON TUNING IN THE INNER EAR

Peter Narins, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 5R01DC000222-11 from National Institute On Deafness And Other Communication Disorders, IRG: HAR

Abstract: Adapted from  s .) The overall goal of the proposed research is a deeper understanding of the anatomical and neural bases of frequency selectivity in the vertebrate auditory system. In particular, the primary objectives of the proposed research are two to provide insights into the mechanisms underlying stimulus interactions which affect tuning in the vertebrate auditory system, and to gain an understanding and appreciation of the cellular bases of frequency resolution. To accomplish the first of these objectives the investigators will (1) elucidate the underlying relationship between two-tone suppression and tuning in the auditory nerve by examining and comparing their temperature dependencies, (2) quantify the effect of contralateral sound on the tuning properties of single auditory nerve fibers, and (3) systematically study the effect of low-level vibratory stimulation on the auditory tuning properties of individual low-frequency auditory neurons. To carry out the second objective, s will (1) precisely characterize membrane currents of auditory hair cells to determine their temperature dependencies, and thus to assess their contribution to tuning, and (2) relate anatomical fine structure (cell body dimensions, axon dimensions, innervation pattern) to tuning properties of identified auditory nerve fibers. Such data that result from this structure-function approach will be rich in implications regarding the anatomical and neural substrate underlying the processing of complex sounds, and that this work will serve as a model for understanding fundamental problems of human speech and music perception in adverse (noisy) environments.

Keywords: auditory discrimination, auditory feedback, biological information processing, ear hair cell, sequential perception, sound frequency, acoustic nerve (VIII), alternatives to animals in research, auditory pathway, auditory stimulus, auditory threshold shift, cell membrane, efferent nerve, evoked potential, innervation, neuroanatomy, noise, psychoacoustics, single cell analysis, stimulus /response, temperature, vibration, Anura, fresh water environment, patch clamp

Project start date: 1983-07-01

Project end date: 1995-06-30

5R01DC000222-11 (1994): $178366

5R01DC000222-10 (1993): $173760

5R01DC000222-09 (1992): $164584

5R01DC000222-13 (1996): $175806

AUDITORY SYSTEM RESPONSE TO AIRBORNE AND SEISMIC STIMULI

Peter Narins, Professor
Physiological Scienceuniversity Of California Los Angeles
office Of Research Administration
los Angeles, Ca 90095

Grant 2R01DC000222-17 from National Institute On Deafness And Other Communication Disorders, IRG: ZRG1

Abstract: The overall goal of the proposed research is a quantitative of the structural and physiological constraints on low-frequency selectivity in the vertebrate auditory system. In particular, the primary objectives of the proposed research are to gain an understanding and appreciation of the mechanical and electrical factors underlying airborne, substrate-borne and combination (bimodal) stimulus reception, and to provide further insight into the mechanisms underlying stimulus interactions which affect tuning in the vertebrate inner ear. To accomplish these objectives, a series of five detailed investigations will be performed in order to a (a) directly measure the motion of the middle ear ossicles in amphibians in response to airborne sound, substrate-borne vibration and bimodal stimulation, and thus more precisely define the role of these structures in low-frequency reception, (b) characterize the airborne and seismic response properties of the middle ear ossicles of two other "low- frequency" animals- the common and golden mole- and thus extend our observations to fossorial mammals, (c) quantify the extent to which the tectorial membrane responds to low-frequency sound and vibration in order to elucidate the role of this structure in bimodal processing, (d) systematically compare synaptic release in low-frequency (bimodal) and high-frequency (unimodal) hair cells from the amphibian papilla by tracking correlated capacitance changes in response to depolarization, and (e) extend our investigation of the nonlinear interactions between acoustic and seismic stimuli to the bimodal fibers in the eighth nerve. The data that result from this integrative structure-functional and neuroethological approach will be rich in implications regarding the anatomical and neural substrates underlying the processing of sound-vibration complexes; thus this work is expected to provide a framework for understanding the relationship between air-conducted and bone-conducted sound transmission in animals, including humans

Keywords: auditory ossicle, auditory pathway, auditory stimulus, ear hair cell, neural information processing, sound frequency, vibration Amphibia, Mammalia, Rana, voltage /patch clamp

Project start date: 1983-07-01

Project end date: 2005-06-30

2R01DC000222-17 (2000): $501386

From Infra- To Ultrasound: Diversity In Acoustic Processing By The Vertebrate Ear

Peter Narins, Professor
University Of California Los Angeles Office Of Research Administration Los Angeles, Ca 90095

Grant 2R01DC000222-23A1 from National Institute On Deafness And Other Communication Disorders, IRG: AUD

Abstract: The overall goal of our laboratory is a richer understanding of the structural and physiological bases of the frequency selectivity or tuning in the vertebrate auditory system. Driven by a knowledge of the animal s acoustic behavior in its natural habitat, our primary objectives for the proposed research are threefold (1) to apply modern techniques to provide new insights into the physiological and biophysical mechanisms underlying the localization of airborne sound and substrate-borne vibration in the vertebrate ear, (2) to gain an understanding and appreciation of the mechanisms underlying the electrical and mechanical cellular processes that modulate and sculpt low-frequency selectivity in the auditory periphery, and (3) to explore the physiological bases underlying the newly-discovered remarkable ultrasonic sensitivity in the amphibian ear. To accomplish these objectives, a series of four detailed investigations will be performed in order to (a) directly measure the motion of the middle ear ossicles in a "low-frequency" animal, the golden mole, in order to characterize the directional responses of the middle ear ossicles to airborne and seismic stimuli- and thus extend our observations to a subterranean seismic specialist, (b) systematically compare both receptor pharmacology and ionic current kinetics in the same hair cell preparation to directly test the effects of exogenous agents on tuning properties of low-frequency hair cells, (c) examine the calcium-calmodulin- dependent contractile mechanism mediating slow motility in response to extracellular stimuli in vertebrate hair cells, and (d) characterize the tuning of the peripheral auditory system of a high-frequency specialist and to determine the mechanisms subserving this tuning. The data that result will be rich in implications regarding the processing of airborne sound and substrate vibration as well as the role of efferent-mediated feedback in frequency tuning. Thus, this work is expected to provide a framework for understanding both airborne and bone-conducted sound transmission and tuning in animals, including humans. Of major current interest is the putative role of the efferent system in the genesis of frequency selectivity and protection against noise overstimulation. Ultimately, our research may lead to new therapeutic approaches to treatment of hyperacusis and noise-induced tinnitus, two known syndromes in which efferent system malfunction has been implicated.

Keywords: auditory ossicle, auditory pathway, auditory stimulus, ear hair cell, neural information processing, sound frequency, vibration, Amphibia, Mammalia, Rana, voltage /patch clamp

Project start date: 1983-07-01

Project end date: 2011-06-30

2R01DC000222-23A1 (2006): $416754

BIOLOGICAL CONSTRAINTS ON TUNING IN THE INNER EAR

Peter Narins, Professor
Physiological Sciencesuniversity Of California Los Angeles
office Of Research Administration
los Angeles, Ca 90095

Grant 3R01DC000222-14S1 from National Institute On Deafness And Other Communication Disorders, IRG: HAR

Project start date: 1983-07-01

Project end date: 2000-06-30

3R01DC000222-14S1 (1998): $26854